Champion’s fine wire center and fine wire dual ground electrodes require less voltage to jump the plug gap, which translates into fewer misfires. This fine wire design also reduces quenching, so more of the heat generated by the ignition is available to the air/fuel mixture and not absorbed by the center and ground electrodes. Side discharge dual ground electrodes maximize deposit scavenging and extend plug life. 13/16 male threaded upper shell for use with a transformer coil ignition system. Approved by Canadian Standards Association for Class1 Group D Division 2 hazardous location use.